Rotary fluid pressure device having free-wheeling capability

Abstract

A rotary fluid pressure device is disclosed of the type including housing means defining a fluid inlet (57) and a fluid outlet (61) and including some form of rotary fluid energy-translating displacement mechanism associated with the housing. In one embodiment of the invention, the displacement mechanism comprises a gerotor gear set (17) including a housing member (22), an internally-toothed ring (23), and an externally-toothed star (27). Included is a free-wheeling mechanism (71) having an engagement member (73) and an actuation means (81) operable to move the engagement member between first and second positions. In a first position, the engagement member (73) prevents rotational movement of the ring (23) and the star (27) has its normal and orbital rotational movement to define expanding (28) and contracting (29) fluid volume chambers. In a second position, the engagement member (73) permits the ring (23) to rotate freely and the star (27) and ring (23) rotate together such that the fluid volume chambers neither expand nor contract and no fluid is displaced from the displacement mechanism.

I claim: 
     
       1. A rotary fluid pressure device of the type including housing means defining inlet means and fluid outlet means; a rotary fluid energy-translating displacement means associated with said housing means and including a rotary assembly and a normally stationary reaction-torque-receiving means, operably associated with said rotary assembly and with said housing means whereby, when said reaction-torque-receiving means is stationary, rotation of said rotary assembly defines expanding and contracting fluid volume chambers, said rotary fluid energy-translating displacement means comprising a means of the type wherein said normally stationary reaction-torque-receiving means defines a fluid chamber, and said rotary assembly is disposed within said reaction-torque-receiving means to separate said fluid chamber into said expanding and contracting fluid volume chambers in response to said rotation of said rotary assembly; means operable to communicate fluid from said fluid inlet means to said expanding fluid volume chambers and from said contracting fluid volume chambers to said fluid outlet means; input-output shaft means and means operable to transmit torque between said input-output shaft means and said rotary assembly; characterized by: (a) an engagement member operably associated with said housing means and said normally stationary reaction-torque-receiving means; and   (b) actuation means operably associated with said engagement member and operable to move said engagement member between: (i) a first position in which said engagement member is disposed to prevent rotational movement of said reaction-torque-receiving means relative to said housing means, whereby said rotary assembly has said normal rotation to define said expanding and contracting fluid volume chambers; and   (ii) a second position in which said engagement member is disposed to permit rotational movement of said reaction-torque-receiving means relative to said housing means, whereby rotation of said rotary assembly does not result in the normal relative movement between said reaction-torque-receiving means and said rotary assembly, and said fluid volume chambers do not expand and contract.     
     
     
       2. A rotary fluid pressure device as claimed in claim 1 characterized by said valve means comprising a normally stationary valve member defining a plurality of normally stationary fluid passages in fluid communication with said expanding and contracting fluid volume chambers. 
     
     
       3. A rotary fluid pressure device as claimed in claim 2 characterized by said normally stationary valve member comprising a valve plate operable to rotate relative to said housing means, said valve plate defining said normally stationary fluid passages, and means for connecting said valve plate for rotation with said reaction-torque-receiving means when said engagement member is in said second position. 
     
     
       4. A rotary fluid pressure device as claimed in claim 1, characterized by said rotary fluid energy-translating displacement means comprising an internal gear set, said reaction-torque-receiving means comprising an internally-toothed outer gear member and said rotary assembly comprising an externally-toothed inner gear member. 
     
     
       5. A rotary fluid pressure device as claimed in claim 4, characterized by said device further comprising a housing member associated with said housing means and defining a generally cylindrical inner surface, said outer gear member being disposed within said cylindrical inner surface of said housing member. 
     
     
       6. A rotary fluid pressure device as claimed in claim 5, characterized by said engagement member being operably associated with said housing member and with said internally-toothed outer gear member, said first position comprising said engagement member preventing rotational movement of said outer gear member relative to said housing member, and said second position comprising said engagement member permitting rotational movement of said outer gear member relative to said housing member. 
     
     
       7. A rotary fluid pressure device as claimed in claim 1 characterized by said normally stationary reaction-torque-receiving means comprising an eccentric ring member defining a cam surface, said cam surface defining said fluid chamber and said rotary assembly comprises a rotor member and a plurality of vane members normally operable to engage said cam surface during rotation of said rotary assembly. 
     
     
       8. A rotary fluid pressure device as claimed in claim 1 characterized by said normally stationary reaction-torque-receiving means comprising an eccentric ring member, and said rotary assembly comprising an internally-toothed member and an externally-toothed member eccentrically disposed therein, said toothed members being in toothed engagement with each other and defining therebetween a crescent-shaped space, said eccentric ring member further comprising a crescent member disposed in said crescent-shaped space to separate said crescent-shaped space into said expanding and contracting fluid volume chambers. 
     
     
       9. A rotary fluid pressure device of the type including housing means defining fluid inlet means and fluid outlet means; a rotary fluid energy-translating displacement means associated with said housing means and including an internally-toothed assembly and an externally-toothed member eccentrically disposed within said internally-toothed assembly, and normally having orbital and rotational movement relative thereto, the teeth of said members normally interengaging to define expanding and contracting fluid volume chambers during said orbital and rotational movement; valve means normally operable in response to at least one of said movements to communicate fluid from said fluid inlet means to said expanding fluid volume chambers and from said contracting fluid volume chambers to said fluid outlet means; input-output shaft means and drive shaft means operable to transmit torque between said input-output shaft means and said externally-toothed member; characterized by: (a) said internally-toothed assembly comprising a housing member associated with said housing means and defining a generally cylindrical inner surface, and an internally-toothed member rotatably disposed within said cylindrical inner surface of said housing member;   (b) an engagement member operably associated with said housing member and said internally-toothed member; and   (c) actuation means operably associated with said engagement member and operable to move said engagement member between: (i) a first position in which said engagement member is disposed to prevent rotational movement of said internally-toothed member relative to said housing member, whereby said externally-toothed member has said normal orbital and rotational movement relative to said internally-toothed member to define said expanding and contracting fluid volume chambers; and   (ii) a second position in which said engagement member is disposed to permit rotational movement of said internally-toothed member within said cylindrical surface of said housing member, whereby rotation of said externally-toothed member does not result in any relative movement between said internally-toothed member and said externally-toothed member, and said fluid volume chambers do not expand and contract.     
     
     
       10. A rotary fluid pressure device as claimed in claim 9 characterized by said rotary fluid energy-translating displacement means comprising a gerotor gear set, said internally-toothed member comprising a gerotor ring having a plurality N+1 of internal teeth, and said externally-toothed member comprising a gerotor star having a plurality N of external teeth. 
     
     
       11. A rotary fluid pressure device as claimed in claim 10, characterized by said valve means comprising a normally stationary valve member defining a plurality N+1 of normally stationary fluid passages, each of said normally stationary fluid passages being in fluid communication with one of said fluid volume chambers, said valve means further comprising a rotary valve member defining a plurality N of valve passages, said rotary valve member rotating at the speed of rotation of said gerotor star, the resulting communication between said rotary valve passages and said stationary fluid passages comprising low-speed, commutating valving. 
     
     
       12. A rotary fluid pressure device as claimed in claim 11 characterized by said normally stationary valve member comprising a valve plate operable to be rotatable relative to said housing means, said valve plate defining said normally stationary fluid passages, and means for connecting said valve plate for rotation with said internally-toothed member when said engagement is in said second position.